2004 dodge neon and white smoke

Evap system has many parts , cannister,vent and purge valves ,fuel tank and cap, first is the fuel cap on and is the seal in good shape. You will need to inspect all vauum hoses that leave the cannister if all ok then get the valve and solenoid tested for stuck open

I don't know but if you can again check for the ODB2 diagnostic code it might provide some light on the problem

I hope this helps.

Try checking the gas cap first off. 95% of the time, an EVAP code, (purge solenoids, or any EVAP code) could be caused by a lose gas cap, or a defective gas cap.

And I know on SOME neons, the evap canister purge solenoid is located on a bracket attached to the air cleaner. Hope this helped.

Sounds like your car is on engine safe mode. This happen when the computer finds a problem and it goes into the mode to protect further damage to the car. You might be able to take it to a place like auto zone for a free computer test.

Hope this helps,
-david

What does that mean? The Powertrain Control Module (PCM) at different times performs various tests on the EVAP system. OBD II Enhanced EVAP systems are in place to keep fuel tank vapors from venting into the atmosphere, and instead purges them into the engine to be burned. Regular pressure tests are conducted by the PCM to monitor the sealed system for leaks. The PCM monitors the EVAP system pressure by watching the fuel tank pressure (FTP) sensor. When the sensor indicates a small leak in the EVAP system, this code is set.
FB.init("dd7d9e9681341cde77587bc6a2029f6f"); OBD-Codes.com on Facebook Potential Symptoms There will likely be no noticeable symptoms other than the Malfunction Indicator Lamp (MIL). This is because the EVAP system is a closed system and only controls fuel tank vapors, not engine management.
Causes Usually this P0456 code is caused by an incorrect or faulty gas cap. Filling the fuel tank with the engine running could conceivable cause this code as well or if the cap wasn't properly tightened. Any of the following could also be the cause:

• A small leak in any of the EVAP hoses or fuel tank hoses
• A small leak in the purge valve or vent valve
• The EVAP Canister may be leaking

Possible Solutions First, using a scan tool activate the vent solenoid, sealing the system. Then monitor the fuel tank pressure (FTP) sensor. If the system is sealing properly, the number will stay consistent. If is isn't, the pressure sensor will show that as well. If the system slowly leaks, use a smoke machine and watch for smoke exiting the system at any EVAP component. Any where there is smoke exiting the system, that is the faulty component. Do not pressurize the EVAP system with air pressure. Doing so can damage the purge and vent solenoids in the system.

It's telling you that the pcm has a set code in the menory. To find out the code take the car to a auto zone parts place to have the pcm scaned free. Once you get the results from them you will know what the pcm is trying to tell you. At that point you can repair or replace the item that is causing the problem. Hope this will help you.

Take the car to an auto parts place and have them run a scan on the car (PCM) powertrain control module. Auto zone does it for free, The pcm has a code set in it and by scanning it you can find out what is wrong,and then you can correct the problem. Hope this will help you.

Do you know where the leak is ,or what is causing it?
Check all the EVAP hoses in the system.
Pretty hard to test without,pressure,vacuum or smoke machine and system knowledge

a small evap leak is often interpreted as a loose gas cap , which it can be , it means the evap systems integrity has been breached , it can be an electrical solenoid , switch or just a vacuum line in the system . a bidirectional scanner can run the evap test after checking the gas cap , most well equipped shops can hook up a smoke machine to the evap system service port and run the smoke test , it there is a leak you will see the smoke , makes the diagnosis quickly . get an estimate from a reputable shop , by the way this problem has no effect on drivability , but should be fixed . cheers

P0442--Evap Emission Sys. leak detected small leak
P0455--Evap Emission sys. leak detected gross leak
P0456--Evap Emission Sys. leak detected very small leak